1. Field of the Invention
The present invention relates to fuel metering systems associated with, for example, internal combustion engines and more particularly relates to a pressure regulator which adjustably meters fuel flow to a carburetor or the like, fuel adjustments corresponding to changes in engine operating conditions such as vacuum pressure changes.
2. General Discussion and Prior Art
With the increase in cost of all types of energy, and especially with the increase in cost of fuel for transportation, a great need exists for devices which more efficiently meter fuel to an engine and still maintain proper engine operation.
It is a generally known fact that vacuum pull, in terms of inches of mercury, varies accordingly with engine operating conditions, in terms of throttle movement, engine loads and engine speeds. It logically follows that by limiting the fuel pressures to desireable minimum levels for each or most of these variable engine operating conditions, this should most certainly prove most beneficial for energy conservation.
A major object of the present invention is to provide a simplified, but completely variable precisely adjustable fuel pressure regulator in order to precondition a fuel supply in terms of pressure values subject to the known requirement of fuel metering systems being used.
Additionally, an object of the present invention is to modify fuel pump characteristics more favorably under various engine operating conditions. With the present invention, the fuel supply metered to a carburator can be adjusted under any of the following varying operating conditions: (1) when operating conditions are influenced by the temperature, (2) when idling, (3) when operating conditions are influenced by throttle position or movement, (4) when operating conditions are influenced by various loads, accelerating, or cruising, (5) when operating conditions are influenced by varying speeds, cruising and high speeds or low speeds, and (6) when operating conditions are influenced by simultaneous loads and speeds such as low speed acceleration and high speed cruising and/or high speed acceleration and low speed cruising.
The vacuum pressure normally rises within an internal combustion engine when the engine experiences low loads and idling. In such instances the vacuum pressure is normally, for example, eighteen (18) to twenty (20) inches of mercury. When the loads are very low on the engine, such as when idling or cruising, and pressures are high, it is desireable to have a minimum amount of fuel flowing to the carburetor. The present invention provides an air-fuel metering pressure regulator which utilizes an engine vacuum pressure to vary the quantity of fuel which flows through the metering system to the carburator under varying operating conditions. The device makes changes in the quantities of fuel flowing to the carburator based on changes in the vacuum pressure of the engine.
Another object of the invention is to provide accessible or external means by which the pressure regulator of the present invention can be independently varied and preset by means of extremely fine thread adjustments.
Another object of the invention is to provide an independent assembly specifically constructed for installations within any available space between a fuel metering system and the fuel pump itself such as occurs within replacement markets, per se.
Another object of the invention is to provide an upgrader variable pressure regulator, in all respects internally similar as herein described excepting that the outer housing configurations can be changed for anticipated and unitized construction or assembly as a component part of a fuel metering system proper as may apply in the case of original markets.
3. General Discussion of the Present Invention
The present invention in the preferred embodiment is comprised of a housing having two cooperating half bodies. First, a vacuum chamber body and secondly a fuel chamber body. The vacuum chamber and fuel chamber bodies are joined together with the face portions enclosing a larger vacuum diaphragm therebetween. This diaphragm is provided with a central diaphragm clamp screw which abuts alternatively a similar but smaller fuel diaphragm clamp screw in the central part thereof. The general configuration shows that the inner portion of each half body are specifically recessed to provide (a) employing a ventilated diaphragm support ring on the vacuum side of the large diaphragm, and (b) a ventilated compression chamber between both large and small diaphragms, and (c) a reduced fuel metering chamber directed to allow the central fuel diaphragm clamp screw to directly activate the fuel needle protruding therein; but limited to the movements of the large vacuum diaphragm as controlled by a vacuum/spring reactions of the travel limits established and opposed by extremely fine adjustable travel control screws, per se.
Thus within the vacuum chamber body, this provides greater and faster responses from the alternate vacuum levels while the independent and smaller fuel chamber diaphragm consequently offers less resistance, despite being influenced by varying fuel pump pressures. This arrangement allows close proximity and direct contact between both diaphragms and the fuel metering needle for quick reactionary responses due to vacuum changes; while still providing two opposing but finely adjustable travel stop screws by which to limit low and high fuel pressure levels.
The vacuum chamber is provided with a vacuum connection tap to which a vacuum source, such as the vacuum line from the inlet manifold of a internal combustion engine can be connected. Changes in vacuum pressure reciprocate the large diaphragm alternately toward the control screws of both diaphragms and away from the needle valve thereby closing the needle valve against an associated seat, thus restricting the flow of fuel through the device, away from the vacuum diaphragm control-stop screw towards the needle valve thereby allowing greater flow of fuel through the device. The fuel chamber body is provided with a fuel entry connection from the fuel pump and a fuel outlet connection for alignment with the carburetor or fuel metering system employed. Further, it is recommended that a restricted fuel by-pass line be connected with the fuel supply tank in order to prevent or eliminate the accumulation of air-pockets generally created by the fuel pump itself, particularly when used with all-pressure systems and ideally shown by FIG. 1.
An alternative embodiment provides a single diaphragm in place of the two diaphragms (the vacuum diaphragm and the fuel diaphragm) of the preferred embodiment. An alternate embodiment of the needle valve arrangement provides for the needle valve to be attached to the fuel chamber diaphragm in order to achieve greater flexibility and control of the pressurized fuel in order to obtain precise fuel metering.